What's wrong with Arizona Diamondbacks' Trevor Bauer?

Whether or not Trevor Bauer gets another turn in the rotation, the easy thing to say is he wasn't ready in the first place. The easy conclusion to reach is that his high walk totals in the minor leagues were a harbinger of the struggles we've witnessed in four big league starts.

And that could well be the case. In 16 1/3 innings, Bauer has walked 13 batters, five of whom have come around to score.

But maybe it's not that simple. Certainly there have been times in his four starts when he's nibbled too much, when he's gone for the strikeout, when he hasn't shown good "pitch efficiency."

But there were other factors, as well. In his first two starts, his curveball -- his best secondary pitch -- was wildly inconsistent. In those games, he found himself working without the pitch he went to most often to put hitters away. The curveball wasn't there again on Tuesday night - but then again neither were any of his other pitches.

Maybe that stuff happened in the minors and we just didn't hear about it. Maybe he was bouncing curveballs and was all over the place with his fastball command, only he got away with it because the hitters were less patient. Maybe he was making the same number of mistakes in the minors as he has in the majors.

Or maybe this version of Trevor Bauer isn't the same as the one from the minors. Perhaps he is giving big league hitters too much credit, pitching them too carefully. Perhaps he can't get comfortable on the mound. Maybe it's nerves. Maybe he can't get a good grip on the major league ball, which has small but discernible differences from the balls they use in the minors.

High walk totals or not, it seems hard to believe that the guy who struck out 116 in 93 innings with a 2.23 ERA in the minors is the same guy who has struggled like this in the big leagues.

Sure, the jump to the big leagues is significant. But this isn't a deception guy with no stuff. This isn't a one-trick pony. This is a guy who scouting directors thought was close to being major league ready when he was at UCLA last year.

Has he struggled because he wasn't ready for the majors? Or has he struggled because, simply, he's had a few bad starts?

Notable: Cahill gave up three runs in seven innings Sunday against the Phillies, handing a one-run lead over to the bullpen, which wasn't able to hold it. His past couple of starts have been solid, but his second half has been only fair; he has a 4.15 ERA in five starts since the All-Star break. Cahill hasn't pitched as effectively at home, with a 4.87 ERA in 10 starts at Chase Field. ... After missing much of last season following elbow surgery, Strasburg has stayed healthy this year and performed alongside the better starters in the majors. He leads the league with 160 strikeouts, despite being tied for 41st in the league in innings pitched. (The Nationals are limiting his innings following surgery, and are planning to shut him down before the end of the season.) According to Fan Graphs data, Strasburg has the highest average fastball velocity at 95.8 mph. He faced the Diamondbacks once during his rookie season, giving up one run in five innings with no walks and seven strikeouts.